Conventionally, a cartridge system has been employed in image forming apparatuses, where process cartridges, drum cartridges, and developing cartridges are detachably mounted to the apparatus main body of the image forming apparatus. The system of these cartridges enables the user him/herself to perform maintenance of image forming apparatuses without depending on a serviceman, which has markedly improved operability.
Accordingly, the cartridge system is in widespread use in image forming apparatuses.
Further, there is a contact developing system, where the photosensitive drum and developing roller are brought into contact to performed developing, when forming an image. There has been proposed a developing cartridge having a pressing unit in the developing cartridge, for bringing the photosensitive drum and the developing roller into contact (e.g., Japanese Patent Laid-Open No. 2011-39564 and Japanese Patent Laid-Open No. 2010-26541).
Now, the photosensitive drum and developing roller in a contact developing system preferably are spaced when not forming images, from the perspective of stability of image quality, and longevity of the photosensitive drum and developing roller.